Gear reduction



Nov. 26, 1940. I v v. c. HODGES 2,222,314

GEAR REDUCTION Filed Dec. 7, 1939 IN VENT QR. Vera C Hoqyes ATTORNEY.

Patented Nov. 26, 1940 UNITED STATES PATENT OFFICE 5 Claims.

My invention relates to a gear reduction and has as its object theprovision of a gear reduction unit that will require a minimum of spaceand yet produce a very substantial reduction.

Reference is made to my co-pending application Serial No. 397,937 filedcontemporaneously herewith, for a clutch.

The invention also comprises novel details of construction and novelcombinations and arrangements of parts, which will more fully appear inthe course of the following description. However, the drawing merelyshows and the following description merely describes an embodiment ofthe present invention, which is given by way of illustration or exampleonly.

In the drawing, like reference characters designate similar parts in theseveral views.

Figure 1 is a longitudinal section of an embodiment of my invention.

Figure 2. is a broken, transverse section taken on the line 2-2 ofFigure 1 Figure 3 is a broken, transverse section taken on the line 3-3of Figure 1.

Figure 4 is a section taken on the line 44 of Figure 2, illustrating anoffset shaft utilized in the embodiment.

Referring more in detail to the drawing, a housing 5 is provided for theembodiment. A head 6 is bolted to the housing, as suggested at I. Boltedto the head 6, interiorly of the housing 5 is an internal ring gear 8.Bolts 9 secure the ring gear 8 to the head 6.

The head 6 has an opening I0 for a shaft I2. The shaft is concentricwith the ring gear 8. A yoke I3 is mounted on the shaft I2 and carriespinion gears I4 and I5 which mesh with the ring gear 8 at substantiallyopposite points therein. A spur gear I6 is integral with the shaft I2and meshes with each of the pinion gears I4 and I5. The yoke I3 providesa race for ball bearings IT. The inner ring of the race is shown at I8,which is mounted on the shaft I2. These bearings provide a substantiallyfriction-free bearing for the shaft I2.

The pinion I5 is free to rotate on a shaft I9, while the pinion I4 isfree to rotate on a shaft 20. The shaft 20 has an ofiset portion 2|,upon which is rotatably carried a pinion gear 22.

An internal ring gear 23 is free to rotate within the housing 5. Anannular bearing plat 24 is arranged in the housing 5 around a portion ofthe member 23. The spur gear 22 meshes with the gear 23, while a spurgear 25 on the shaft I9 also engages the teeth of the ring gear 23, at

26 together with the yoke I3 supports the shafts I9 and 20 upon the mainshaft I2. As with the case of the yoke I3, the yoke 26 provides a racefor ball bearings 21. The other annular mem-- ber 28 of the race ismounted on the shaft I2:

A spur gear 29 is arranged on the shaft I2 in between and meshing withpinion gears 22 and 25. Ball bearings 30 are provided for the shaft I2within an internal flange 3| of the element 23. A hearing 32 and bushing33 are also arff)" shaft 20 is sufiicient to offset the spur gear 22 20:

one-half of one of its teeth. Also in the embodiment shown, the spurgear 29 has one more tooth than the spur gear I6, while the ring gears 8and 23 have the same number of teeth.

Moreover, in the embodiment shown, the pinion.

gears I4 and 22 have the same number of teeth and the spur gears I5 and25 have the same number of teeth. I

An'annulus 40 maintains the rotary member 23 in position. The annulus 40may be supported 30 by the same member (not shown) that supports thebearing 32.

In the operation of the device, driving means is connected with theshaft I2 and fastened thereon by key 34 or other suitable means. Ro- 35tation of the shaft I2 causes rotation of all of the planetary gears I4,I5, 22 and 25 around the spur gears I2 and. 29 respectively. Therelatively fixed ring gear 8 causes independent rotation of the piniongears I4 and I5 around their shafts 40 20 and I9, thus rotating the yokeI3 and through the shafts I9 and 20 rotating the yoke 26.

Rotation of the yoke 26 and of the spur gear 29 effects rotation of thering gear 23 at a reatly reduced speed due to the single toothdifference 5 between the spur gears 29 and I6. It is understood that thediiference in the number of teeth between the spur gears I6 a d 2 mayvary otherwise than stated.

While I have illustrated and described what I 50 now regard as thepreferred embodiment of my invention, the construction is, of course,subject to modifications without departing from the spirit and scope ofmy invention. I, therefore, do not wish to restrict myself to theparticular 55 form of construction illustrated and described, but desireto avail myself of all modifications which may fall within the scope ofthe appended claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. Gear reduction means comprising relatively fixed and rotary ringgears, a shaft having spur gear means thereon, a pair of planetary gearsengaging one of the spur gears at substantially opposite points on theperiphery of the spur gear means, and the planetary gears engaging thefixed ring gear, a yoke floating around the shaft and maintaining theplanetary gears in said positions, a second pair of planetary gearsengaging the rotary ring gear and engaging the other spur gear atsubstantially opposite points" on the periphery thereof, a yoke floatingaround the shaft and maintaining the latter planetary gears in theirsaid positions, and a pair of shafts secured in connection with saidyokes, each shaft supporting one of the planetary gears of each pairthereof, and one of said shafts having its gear supporting portionsoffset with respect to one another.

2. Gear reduction means comprising two elements having substantiallyidentical ring gears, one ring gear being fixed and the other beingrotary, substantially identical planetary gears engaging the ring gears,one planetary gear being approximately a half a tooth at the side of theother planetary gear, a single ofiset shaft for the two planetary gears,the offset being sufficient to arrange the one planetary gear a half atooth at the side of the other, and different spur, driving gear meansengaging the planetary gears.

3. Gear reduction means comprising two elements having substantiallyidentical ring gears, one ring gear being fixed and the other beingrotary, planetary gears engaging the ring gears, one planetary gearbeing approximately a half a tooth at the side of the other planetarygear, a single offset shaft for the two planetary gears, the offsetbeing suificient to arrange the one planetary gear a half a tooth at theside of the other, and spur gears respectively engaging the planetarygears, the gear ratio of one planetary gear to its engaged spur gearbeing different than the gear ratio of the other planetary gear to itsengaged spur gear.

4. Gear reduction means comprising two ele- "ments having substantiallyidentical ring gears,

one ring gear being fixed and the other being rotary, substantiallyidentical planetary gears engaging the ring gears, one planetary gearbeing approximately a half a tooth at the side of the other planetarygear, a single offset shaft for the two planetary gears, the offsetbeing suflicient to arrange the one planetary gear a half a tooth at theside of the other, a main shaft, and spur 'gears on the shaft havingdifferent numbers of teeth. and respectively engaging the planetarygears.

5. Gear reduction means comprising a shaft having different spur gears.thereon, two elements having substantially identical ring gears, onering gear being. fixed and the other being rotary, substantiallyidentical planetary gears engaging the fixed ring gear and disposed atsubstantially opposite points of one of the spur gears and in engagementtherewith, a yoke floating around the shaft and maintaining theplanetary gears in said positions, another set of planetary gears thatare substantially identical with each other andsubstantially identicalwith the first-mentioned planetary gears, the second-mentioned set ofplanetary gears engaging the rotary ring gear and engaging the otherspur gear at substantially opposite points thereon, a yoke floatingaround the shaft and maintaining thesecond-mentioned planetary-gears intheir said positions, a planetary gear. of one set: being axially offsetwith respect to the corresponding planetary gear of the other set, andmeans maintaining the sets of planetary gears in such position with theone gear of one set offset with respect to the corresponding gear of theother set.

VERA C. HODGES.

